Have a problem with Google play store not signing in and downloading an application. When I open Google play it displays " Authentication is required. You need to sign into your Google account." with a retry button. Click retry but nothing happens. I went to settings and switched account but I can't download a certain app. When I try to download it displays the same message. Have already restarted the phone, stopped the store from running, and cleared the cache. Any suggestions? Please help.

 

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